This invention relates to an interior rearview mirror attached to a ceiling near a driver""s seat or an inside of a windshield in a vehicle, and particularly to an interior rearview mirror capable of reducing glare of light from headlamps of succeeding vehicles during night driving.
Light emitted from the headlamps of succeeding vehicles and directly reflected off the interior rearview mirror during night driving would dazzle a driver and thus threaten the safety of driving. Therefore, a reflection angle of the interior rearview mirror provided in the vehicle may be changed to an angle suitable for an antiglare purpose with a lever below the mirror operated by a driver.
FIG. 6 is a partially cutaway view, in perspective, of a conventional interior rearview mirror 20. As shown in FIG. 6, the conventional interior rearview mirror 20 is attached with a stay 21 to a ceiling near a driver""s seat in a vehicle or an inside of a windshield. A mirror 22 made up of a prism is held in a groove provided in a mirror housing 23. At a distal end of the stay 21 is formed a ball joint 26, which has a spherical shape. The ball joint 26 is fitted into a socket formed in a midsection of a bracket 24 of the interior rearview mirror 20 so that the bracket 24 is joined to the stay 21.
Accordingly, when the mirror housing 23 is handled to adjust a field of view of the mirror 22, an adjustment in positioning of the mirror 22 is made by turning the bracket 24 about the ball joint 26 provided at the distal end of the stay 21. An antiglare operation to be performed to immediately change the reflection angle of the mirror 22 includes operating (pivoting) a lever 25 engaged with the bracket 24 so as to tilt the mirror housing 23, thereby changing the reflection angle of the prismatic mirror 22. The pivoting operation of the lever 25 is to switch the mirror 22 from a xe2x80x9cDayxe2x80x9d position to a xe2x80x9cNightxe2x80x9d position, or from the xe2x80x9cNightxe2x80x9d position to the xe2x80x9cDayxe2x80x9d position; the tilting operation is to change a reflection angle of the mirror 22 by pivoting the lever 25.
FIG. 7A is a perspective view for explaining an engagement between the bracket 24 and the lever 25 that are depicted in the center of FIG. 6. As shown in FIG. 7A, on right and left sides of an upper portion of the bracket 24 are formed pins 24a, 24a, the bracket 24 is fitted in a concave portion provided in the mirror housing 23, so as to get tilted by pivoting about the pins 24a, 24a. 
On the other hand, while the lever 25 is shaped like a letter T, on right and left ends of the lever 25 are formed pins 25a, 25a as well, and the lever 25 is fitted in a concave portion provided in the mirror housing 23, so as to pivot about the pins 25a, 25a. 
As shown in FIGS. 7A through 7C, an engagement portion 24b of the bracket 24 is formed into an angular ridge, and an engagement portion 25b of the lever 25 is formed into a V-shaped groove. To be more specific, an edge of the engagement portion 24b that forms a ridgeline is brought into contact with a bottom of the V-shaped groove of the engagement portion 25b of the lever 25, and the lever 25 is operated to pivot till one of the sides that form the ridge of the bracket 24 is brought into contact with one of the sides that form the groove of the lever 25.
FIGS. 7B and 7C are right side views of FIG. 7A. FIG. 7B illustrates a xe2x80x9cDayxe2x80x9d condition where the lever 25 is pivoted to a back side; FIG. 7C illustrates a xe2x80x9cNightxe2x80x9d condition where the lever 25 is pivoted to a front side. As shown in FIG. 7B, when the lever 25 is pushed down to the back side, one side of the ridge of the bracket 24 is brought into contact with one side of the V-shaped groove of the lever 25, and this position is maintained. To be more specific, L1+L2 greater than L3 is satisfied where L1 is a length from a center of the pin 24a to a distal end of the engagement portion 24b of the bracket 24; L2 is a length from a center of the pin 25a to the bottom of the V-shaped groove of the lever 25; and L3 is a distance from the center of the pin 24a of the bracket 24 to the center of the pin 25a of the lever 25, and thus the above position is maintained.
At this stage, the lever 25 tilts backward at an angle xcex8 while the bracket 24 tilts frontward at an angle xcex1. In contrast, when the lever 25 is operated to pivot frontward, the lever 25 tilts frontward at an angle xcex8, while the bracket 24 tilts backward at an angle xcex8, as shown in FIG. 7C. Thus, pivoting operation of the lever 25 (at an angle 20) may bring a quick shift in a tilt angle of the mirror 22 at an angle 2xcex1.
As shown in FIG. 7B, for example, where L1 is 40.0 mm, L2 is 2.0 mm, and xcex8 is 25 degrees, xcex1 becomes 1.21 degree, L3 becomes 41.80 mm, and a difference between L1+L2 and L3 becomes 0.2 mm; it thus turns out that L3 is shorter.
However, the conventional interior rearview mirror 20 has an intrinsic disadvantage that the lever 25 is allowed to voluntarily pivot notwithstanding the lever 25 is not operated, when the mirror housing 23 is held and an adjustment is made in a field of view of the mirror 20. This is presumably because the difference between L1+L2 and L3 is small, i.e., the small pivoting angle 2xcex8 of the lever 25 is responsible therefor, and thus a small moment applied to the bracket 24 via the ball joint 26 of the stay 21 causes the lever 25 to switch its position when the mirror housing 23 is moved manually. It is therefore conceivable that providing the lever 25 with a larger pivoting angle 2xcex8 by making an angle of the V-shaped groove of the lever 25 larger could serve to eliminate the above disadvantage. Disadvantageously, however, the larger the angle of the V-shaped groove, the more likely it could become that the ridge of the bracket 24 is easily disengaged from the V-shaped groove of the lever 25.
Moreover, as shown in FIG. 5C that illustrates a conventional combination of mold parts for use with an injection molding machine for making a V-grooved lever 25, a conventional shape of the V-grooved lever 25 requires a slide 28 to form an under side of the lever 25 other than mold parts 26, 27 located at right and left sides of the lever 25, which thus causes an increase in number of mold parts, in structural complexity, and thus in manufacturing cost.
Under these circumstances, the present invention has been created to eliminate the above-discussed disadvantages in prior art.
Therefore, it is an exemplified object of the present invention to provide an interior rearview mirror that includes a lever having a larger pivoting angle so as not to voluntarily pivot when a mirror housing is held and an adjustment is made in a field of view of the mirror, and a bracket having a ridge provided so as not to get disengaged from a V-shaped groove of the lever. Moreover, it is another exemplified object of the present invention to provide an interior rearview mirror that may dispense with a slide or a mold part that forms an under section of the final casting for manufacturing the lever, thereby reducing manufacturing costs.
In order to achieve the above objects, there is provided an interior rearview mirror according to one aspect of the present invention as set forth in claim 1. The interior rearview mirror comprises a stay that is fixed in a vehicle, a bracket that is coupled to the stay with a ball joint formed at a distal end of the stay, a mirror housing that is tiltably pivoted on the bracket, a prismatic mirror that is held in the mirror housing, and a lever that is engaged with the bracket, pivoted in the mirror housing, and operated to pivot so that the bracket may tilt. At a lower end of the bracket are formed a first engageable projection having a projection at a front side and a second engageable projection having a projection at a back side which first and second engageable projections are alternately provided from side to side along the bracket. At an upper end of the lever are formed a straight engaging ridgeline parallel to a pivot axis of the lever, a first engageable depression that is formed from the engaging ridgeline toward a front side of the engaging ridgeline to engage with the first engageable projection, and a second engageable depression that is formed from the engaging ridgeline toward a back side of the engaging ridgeline to engage with the second engageable projection which first and second engageable depressions are alternately provided from side to side along the lever.
In this aspect of the present invention as set forth in claim 1, an engagement portion at which the bracket having a projection and the lever having a depression engage with each other includes a first engagement portion and a second engagement portion. The second engageable projection and the second engageable depression securely engage with each other when the lever is pivoted backward, while the first engageable projection and the first engageable depression securely engage with each other when the lever is pivoted frontward; therefore, a pivoting angle of the lever may be made greater. Moreover, the closer to the pivoting angle, the more securely the depression and projection of the engagement portion engage with each other, and thereby become more difficult to disengage from each other. In addition, an alternate arrangement of the depressions and projections contributes to enhanced stiffness of the engagement portion. Consequently, such an interior rearview mirror as may include a lever allowing a larger pivoting angle and a bracket whose engagement portion never disengages from an engagement portion of the lever may be brought into practical use.
The engaging ridgeline formed at an upper end of the lever is a straight line parallel to the pivot axis of the lever. More specifically, edges of the depressions that are arranged alternately from side to side along the lever are aligned so that each segment is combined to form one straight line.
Accordingly, the depressions (V-shaped grooves) that are provided alternately from side to side along the lever are formed from the engaging ridgeline toward a front or back side of the engaging ridgeline, and thus a slide for forming an under section of the mold as required in a conventional mold having parting lines for manufacturing a V-grooved lever is no more required, with the result that the manufacturing cost of the mold may be reduced.
It is understood that the engaging ridgeline is a ridge line of the lever that forms an axis of engagement between the bracket and the lever, and indicates a vertex from which depressions are formed toward right and left sides when the lever is viewed from a side thereof.
Other objects and further features of the present invention will become readily apparent from the following description of preferred embodiments with reference to accompanying drawings.